Rocking in Presence of Cracking of Masonry Wall Piers

2017 ◽  
Vol 747 ◽  
pp. 678-685 ◽  
Author(s):  
Fabio di Carlo ◽  
Simona Coccia ◽  
Mario Como
Keyword(s):  
Energy Dissipation ◽  
Masonry Wall ◽  
Structural Systems ◽  
Masonry Building ◽  
Masonry Structures ◽  
Structural Components ◽  
Failure Condition ◽  
Triangular Region ◽  
Lower Triangular ◽  
The One

The wall pier represents the vertical element of multi-storey walls with openings, the main resistant structural components of a masonry building. Structural systems of wall piers and spandrels are required to sustain the in-plane seismic actions acting on the wall, opposing with their weights to the action of horizontal forces. The behavior of masonry constructions results to be very far from the one characterizing ductile structures, because of the lack of energy dissipation during the deformation. A strength resource of masonry structures, properly reinforced in order to avoid early local failures, consists in exhibiting rocking behavior, until a failure condition is attained. An investigation on the dynamic behavior of masonry wall piers is carried out by following Housner’s studies and properly introducing the effect of diagonal cracks, shown by typical post-earthquake cracking patterns. As a consequence, the system is characterized by the detachment of a lower triangular region that becomes ineffective during the development of the mechanism and does not oppose with its weight to the overturning. Finally, it is shown that the occurrence of diagonal cracks can be prevented by the execution of suitable retrofit interventions.

scholarly journals Effect of Roof and Diaphragm Connectivity on Dynamic Behaviour of the PP-band Retrofitted Adobe Masonry Structures

2018 ◽  
Author(s):  
Navaratnarajah Sathiparan
Keyword(s):  
Shaking Table Test ◽  
Masonry Wall ◽  
Shaking Table ◽  
Experimental Program ◽  
Masonry Structures ◽  
Test Results ◽  
Structural Components ◽  
Masonry Unit ◽  
Seismic Safety ◽  
Lateral Drift

This paper discusses the shaking table test results of three PP-band (Polypropylene band) retrofitted quarter scale one-story masonry house models with different roof conditions. Better connections between masonry wall and roof connection are one factor to improve the seismic safety of the masonry houses. Past studies show that PP-band retrofitting improves the integrity of structural components and prevent the collapse of masonry structures during an earthquake. Although the effect of masonry unit type, surface plastering, the pitch of the PP-band mesh, PP-band connectivity in mesh and tightness of the mesh attachment to walls were studied by experiment program, the effect of the roof and its diaphragm connectivity on PP-band retrofitted masonry structure is nonexistent. Therefore, an experimental program was designed and executed for an understanding the effect of the roof and its connection on the dynamic behavior of the PP-band retrofitted box-shaped masonry house models. Results reveal that the PP-band retrofitted models with proper roof diaphragm improves the seismic behavior with respect to lateral drift, shear resistance and ductility.

scholarly journals Evaluation of timber floor in-plane retrofitting interventions on the seismic response of masonry structures by DEM analysis: a case study

2021 ◽  
Author(s):  
Alessandra Gubana ◽  
Massimo Melotto
Keyword(s):  
Seismic Response ◽  
Masonry Wall ◽  
Masonry Building ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Cyclic Behaviour ◽  
Out Of Plane ◽  
Dem Analysis ◽  
Side Walls ◽  
Seismic Forces

Abstract The seismic response of existing masonry structures is strongly influenced by floor and roof in-plane properties. An in-plane strengthening intervention is often needed on traditional timber floors to overcome their low in-plane stiffness and to preserve historical buildings. In this study, the effect of un-stiffened and stiffened timber floors on the seismic behaviour of an existing listed masonry building is investigated with dynamic non-linear analyses by means of the Discrete Element Method (DEM). With this approach, the failure processes and collapse sequences of masonry structures can be followed in detail. A previously developed model of the floor cyclic behaviour, based on experimental data, is here applied in the DEM models of the masonry building. Different seismic ground accelerations, different floor types and different wall-to-diaphragm connections are considered. The results highlight the effectiveness of the analysed floor strengthening solution in reducing the out-of-plane displacements of masonry walls. With adequate connections, the reinforced floor is able to transfer the seismic forces to the shear resistant walls up to the shear-sliding collapse of the side walls of the structure. A comparison with the ideal rigid diaphragm case confirms the good performance of the strengthened floors. The small observed out-of-plane displacements are compatible with the masonry wall capacity, and the reinforced floor hysteretic cycles contribute to dissipating part of the input energy. Moreover, different designs of the connections can also cap the transferred seismic forces to an acceptable level for seismic resistant walls.

scholarly journals Seismic Performance of Multistorey Masonry Structure with Openings Repaired with CFRP Grid

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jin-Ben Gu ◽  
Yi Tao ◽  
Ren Xin ◽  
Z. Yang ◽  
Qing-Xuan Shi
Keyword(s):  
Experimental Study ◽  
Energy Dissipation ◽  
Seismic Performance ◽  
Masonry Wall ◽  
Masonry Structure ◽  
Shear Capacity ◽  
Seismic Resistance ◽  
Masonry Structures ◽  
Frp Composites ◽  
Energy Dissipation Capacity

FRP composites have been used for strengthening RC and masonry structures for decades. However, the researches on repairing multistorey masonry structures using FRP grids were relative less. In the present paper, an experimental study on the seismic performance of multistorey masonry structure with openings repaired with CFRP grid is introduced. Specifically, a 1/3-scale three-floor masonry wall with window openings was tested under quasistatic action to simulate the seismic damages. The damaged masonry wall was then repaired by externally bonding CFRP grids to the areas where the cracks intensively occurred. The repaired masonry wall was retested under the same loading to investigate the seismic resistance and assess the recovery attributed from the CFRP grid repairing. The findings of this study showed that CFRP grid repairing could effectively postpone or even prevent the occurrence and development of cracking. The seismic resistance of the masonry, including shear capacity, energy dissipation capacity, deformability, stiffness degradation, and ductility, was restored. The application of CFRP grid may shift the failure mechanism of the multistorey masonry wall. The recommendation of repair scheme for the similar structures was also proposed in accordance with the findings of the present work.

scholarly journals Evaluation of timber floor in-plane retrofitting interventions on the seismic response of masonry structures by DEM analysis: a case study

2021 ◽  
Author(s):  
Alessandra Gubana ◽  
Massimo Melotto
Keyword(s):  
Seismic Response ◽  
Masonry Wall ◽  
Masonry Building ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Cyclic Behaviour ◽  
Out Of Plane ◽  
Dem Analysis ◽  
Seismic Forces

AbstractThe seismic response of existing masonry structures is strongly influenced by floor and roof in-plane properties. A strengthening intervention is often needed for traditional timber floors to overcome their low in-plane stiffness and to preserve historical buildings. In this study, the effects of unreinforced and reinforced timber floors on the seismic behaviour of an existing listed masonry building are investigated with dynamic non-linear analyses by means of the Discrete Element Method (DEM). With this approach, the failure processes and collapse sequences of masonry structures can be captured in detail. A previously developed model of the floor cyclic behaviour, based on experimental data, is applied herein to DEM models of the masonry building. Different seismic ground accelerations, different floor types and different floor-to-wall connections are considered. The results highlight the effectiveness of the analysed floor strengthening solution in reducing the out-of-plane displacements of masonry walls. With adequate connections, the reinforced floor is able to transfer the seismic forces to the shear-resistant walls up to the shear-sliding collapse of the structural sidewalls. A comparison with the ideal rigid diaphragm case confirms the good performance of the strengthened floors. The small observed out-of-plane displacements are compatible with the masonry wall capacity, and the reinforced floor hysteretic cycles contribute to dissipate part of the input energy. Moreover, different designs of the connections can also cap the transferred seismic forces to an acceptable level for shear-resistant walls.

scholarly journals Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2961
Author(s):  
Moein Rezapour ◽  
Mehdi Ghassemieh ◽  
Masoud Motavalli ◽  
Moslem Shahverdi
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Unreinforced Masonry ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Vertical Strip ◽  
Maximum Resistance ◽  
The Cross ◽  
Post Tensioning

This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model's position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.

Seismic Vulnerability Assessment of Masonry Building from Ottoman Period in Bosnia and Herzegovina

2015 ◽  
pp. 734-764
Author(s):  
Mustafa Hrasnica ◽  
Amir Čaušević ◽  
Nerman Rustempašić
Keyword(s):  
Bosnia And Herzegovina ◽  
Seismic Vulnerability ◽  
Stone Masonry ◽  
Masonry Building ◽  
Masonry Structures ◽  
Historical Buildings ◽  
Traditional Art ◽  
South East Europe ◽  
Structural Engineers ◽  
Scale Design

Traditional art of building in Bosnia and Herzegovina comprises brick or stone masonry structures. Most historical buildings belonging to national cultural heritage were made of stone-masonry. The country is situated in seismic active region of South-East Europe. In the case of strong earthquake motion such buildings could suffer heavy damages. Some structural elements of historical buildings, as domes and arches, cracked already by moderate earthquake but without the loss of stability. Substantial damages were caused by recent war disaster. Damages could be accumulated through the history as well. Generally, stone-masonry buildings in Bosnia and Herzegovina can be classified in vulnerability classes between A and C according to European Macroseismic Scale. Design and construction procedures for rehabilitation are presented here with examples of repair and strengthening of mosques, which present historical stone masonry structures dating from the Ottoman period in Bosnia and Herzegovina. Traditional and contemporary materials were used for their rehabilitation. It is important to preserve original forms, especially those of damaged elements. The challenge for structural engineers and architects was to find equilibrium between aesthetical and structural demands.

Seismic Vulnerability Assessment of Masonry Building from Ottoman Period in Bosnia and Herzegovina

2019 ◽  
pp. 1142-1173
Author(s):  
Mustafa Hrasnica ◽  
Amir Čaušević ◽  
Nerman Rustempašić
Keyword(s):  
Bosnia And Herzegovina ◽  
Seismic Vulnerability ◽  
Stone Masonry ◽  
Masonry Building ◽  
Masonry Structures ◽  
Historical Buildings ◽  
Traditional Art ◽  
South East Europe ◽  
Structural Engineers ◽  
Scale Design

Traditional art of building in Bosnia and Herzegovina comprises brick or stone masonry structures. Most historical buildings belonging to national cultural heritage were made of stone-masonry. The country is situated in seismic active region of South-East Europe. In the case of strong earthquake motion such buildings could suffer heavy damages. Some structural elements of historical buildings, as domes and arches, cracked already by moderate earthquake but without the loss of stability. Substantial damages were caused by recent war disaster. Damages could be accumulated through the history as well. Generally, stone-masonry buildings in Bosnia and Herzegovina can be classified in vulnerability classes between A and C according to European Macroseismic Scale. Design and construction procedures for rehabilitation are presented here with examples of repair and strengthening of mosques, which present historical stone masonry structures dating from the Ottoman period in Bosnia and Herzegovina. Traditional and contemporary materials were used for their rehabilitation. It is important to preserve original forms, especially those of damaged elements. The challenge for structural engineers and architects was to find equilibrium between aesthetical and structural demands.

Experimental Test of Welded Wide Flange Fuses

2018 ◽  
Vol 763 ◽  
pp. 414-422 ◽  
Author(s):  
Tony Y. Yang ◽  
Winda Banjuradja ◽  
Lisa Tobber
Keyword(s):  
Energy Dissipation ◽  
Longitudinal Direction ◽  
Elastic Stiffness ◽  
Design Parameters ◽  
Structural Components ◽  
Earthquake Energy ◽  
Aspect Ratios ◽  
Metallic Dampers ◽  
Energy Dissipation Capacity ◽  
Metallic Damper

Metallic dampers are one of the most prevalent structural components that are used to dissipate earthquake energy. A novel metallic damper, named Welded Wide Flange Fuse (WWFF), is proposed in this paper. WWFF utilizes commonly available welded wide flange sections to dissipate the earthquake energy through shear yielding of the web in the longitudinal direction, which makes the WWFF easy to be fabricated and efficient in providing high elastic stiffness and stable energy dissipation capacity. In this paper, a detailed experimental study was conducted to examine the influence on the design parameters (such as aspect ratios and slenderness ratios) on the component response (such as yielding force and elastic stiffness). The result shows that the WWFF has stable energy dissipation capacity which can be used as an efficient and robust metallic damper.

Testing of Masonry Structures for Seismic Assessment

1996 ◽  
Vol 12 (1) ◽  
pp. 145-162 ◽  
Author(s):  
G. Michele Calvi ◽  
Gregory R. Kingsley ◽  
Guido Magenes
Keyword(s):  
Energy Dissipation ◽  
Experimental Evaluation ◽  
Unreinforced Masonry ◽  
Seismic Assessment ◽  
Experimental Techniques ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Seismic Loadings ◽  
Energy Dissipation Capacity ◽  
Reduced Scale

The experimental evaluation of strength, deformability, and energy dissipation capacity of unreinforced masonry buildings subjected to seismic loadings presents unique and complex problems, both for laboratory and field evaluations. The paper addresses these problems, focusing on the relative merits and roles of several experimental techniques, including quasistatic, dynamic, and pseudodynamic loadings at full and reduced scale.

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